SECTION 3: GENERAL INFORMATION

GENERAL

INFO

Do you need to read this section at all?

Many of you reading this manual have a lot of experience in using large mixing consoles. For you battle-scarred pros, Section 2 and the Block Diagram will probably be all that you need to look at.

Then there are those of you who have worked extensively with smaller mixers such as our CR-1604 — but who have less experience with a larger, multi-bus console with lots of gazintas and gozoutas. For you, we recommend at least adding Section 4 (Recording) and/or Section 5 (PA) to your reading list. These chapters cover some of the more unusual or less familiar features of your new 8•Bus console.

Finally, there are those who are either new to using mixers or just like to read even larger quantities of our glib prose. For you, we have provided this short section that discusses the basic concepts and procedures used in recording, mixing and sound reinforcement work. If you can make some sense of it, you’re ready for the next two sections, which relate these concepts to actually configuring and using a Mackie 8•Bus Series mixing console.

Also, if the system Block Diagram does not look as familiar to you as the menu at McD’s, spend a little time in this section.

Headroom

Every electronic circuit also has a point of overload — a clip point, where the voltage simply cannot rise any higher, no matter what the input signal and your fader move would like. This overload, or clipping, will show up as tooth- grinding distortion.

Somewhere between the noise and the clipping is an optimum level for your signal: high enough above the noise floor to render the hiss inaudible, and far enough below the distortion point to allow range for loud peaks of music to pass without clipping. This safe operating zone might be called operating level or nominal level or zero or perhaps line level. The range between your operating level and clipping is called head- room, which defines just how tall your signal can be without having to duck for the rafters.

Your mission as a designated Master of the Levels is to get the low-level signals up to line-level as soon as possible and to keep them there as much as possible. But don’t turn them up too loud.

Unity Gain

On a Mackie 8•Bus console, the easy way to do this is to set all the level controls according to the Sensitivity Adjustment procedure detailed on page 1.

GENERAL INFORMATION

Here is a primer covering a few important ideas you should be on good terms with before you sit down to a mixing console.

LEVELS

Microphones have very

low output levels. Power am-

plifiers have very high output levels. One of the

functions of a mixing console is to amplify or attenuate (reduce) these signal levels properly. Since it’s easy to degrade the signal by not handling levels well, and since it’s your hand on the controls, you should be sure you know how much gain to apply and where to apply it.

Noise

Every electronic circuit produces noise or hiss or hash or buzz, and any noise present on the input of an electronic circuit will be faithfully passed through. Turn it up high enough, and you will hear the noise.

Metering

When the meters read 0dB, the level will actually be +4dBu at the outputs (or –10dBV at the submaster outputs, if you’ve engaged their +4/–10 switches). Don’t pay too much attention to the meters. A meter is an aid, a window looking onto part of the dynamic range of your signal, and it will tell you if your level is in the ballpark, so to speak.

Try to keep your signals in the middle range of the meters, for the most part. If the signal is always very low, you may not be getting the best noise figures you can. If the meter LEDs are always solidly lit from bottom to top, you are likely distorting both the console and your recording tape regularly. Keep the signal in the middle, with occasional peaks into the yellow. Remember, the top yellow LED of the meter (+10) represents an audio level of +14dBu, and the Mackie 8•Bus doesn’t clip until +28dBu. Even banging the meters hard, you still have around 14dB of headroom for your peaks. (The L/R meters have an additional red LED segment to show clipping at +28dBu.). There are not

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